Taxonomy: Formerly placed in the monotypic genus Oroaetus. Voous (1964) suggested that it did not differ sufficiently from Spizaetus to be placed in a separate genus. Amadon (1982) moved this species to Spizastur and later to Spizaetus (Amadon and Bull 1988). The molecular studies of Helbig et al. (2005), Lerner and Mindell (2005), and Haring et al. (2007), based on DNA sequences of mitochondrial and nuclear genes, confirmed that Oroaetus is closely related to Spizaetus and is a sister species to S. ornatus and S. melanoleucus. Their recommendation to merge this species into Spizaetus was adopted by the AOU's South American Classification Committee (Remsen et al. 2009).

Movements: Probably non-migratory.

Habitat and Habits: Prefers undisturbed wet cloud forest on slopes at middle and montane elevations, rarely lower and occasionally as high as páramos in Venezuela. It usually occurs from 1,500 to 2,800 m, but has been recorded from sea level to 3,500 m (Fjeldså and Krabbe 1990, Bierregaard 1994). It soars regularly over forest, sometimes in pairs, especially in the morning. Occasionally seen on an exposed perch, but mostly perches inside forest. more....

Breeding: The nest is a huge structure of sticks placed high in an emergent tree. Clutch size is 1 egg. An egg in the American Museum of Natural history collection taken by Leon E. Miller and H.S. Boyle (unpublished notes) along the Rio Incachaca, Bolivia, was spherical in shape, white with chocolate-brown spots, and measured 51 x 33.5 mm.

Conservation: This species may not be rare as suspected within its altitudinally narrow, but linearly extensive (6,000 km) range, but it is too poorly studied to make any informed judgment about its actual status. Despite its large size, it is difficult to detect because it occurs in such remote and rugged mountain areas. It is doubtless at considerable risk from the loss of primary forest habitat, and reports of birds in partially logged tracts may be of individuals displaced from undisturbed forest. Categorized as Endangered by BirdLife International. more....

Population Estimates: Ferguson-Lees and Christie (2001) estimated a global population size, based on the number of adults and immatures at the start of the breeding season, at 101 to 1,000 individuals, but clearly leaned toward the lower end of this range. BirdLife International (2009) similarly estimated the number of mature birds at 250 to 999.